Under Custom Parts (or any part for that matter), be able to set the price based on a % of the cost of THAT item, not a % of all the parts in the area or all the labor in the area (or proposal). The way you have it, a $5.00 part can only be fixed to a reasonable price, or possibly increased to $40.00 based on the area or proposal totals. In sales, we look at the individual item, not the whole area/proposal.